Utah State University DigitalCommons@USU All Graduate Theses and Dissertations Graduate Studies 5-2019 River Hydrology, Morphology, and Dynamics in an Intensively Managed, Transient Landscape Sara Ann Kelly Utah State University Follow this and additional works at: https://digitalcommons.usu.edu/etd Part of the Physical Sciences and Mathematics Commons Recommended Citation Kelly, Sara Ann, "River Hydrology, Morphology, and Dynamics in an Intensively Managed, Transient Landscape" (2019). All Graduate Theses and Dissertations. 7479. https://digitalcommons.usu.edu/etd/7479 This Dissertation is brought to you for free and open access by the Graduate Studies at DigitalCommons@USU. It has been accepted for inclusion in All Graduate Theses and Dissertations by an authorized administrator of DigitalCommons@USU. For more information, please contact [email protected]. RIVER HYDROLOGY, MORPHOLOGY, AND DYNAMICS IN AN INTENSIVELY MANAGED, TRANSIENT LANDSCAPE by Sara Ann Kelly A dissertation submitted in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY in Watershed Science Approved: __________________________ __________________________ Patrick Belmont, Ph.D. Peter Wilcock, Ph.D. Major Professor Committee Member __________________________ __________________________ Efi Foufoula-Geogiou, Ph.D. Joseph Wheaton, Ph.D. Committee Member Committee Member __________________________ __________________________ Jiming Jin, Ph.D. Richard S. Inouye, Ph.D. Committee Member Vice Provost for Graduate Studies UTAH STATE UNIVERSITY Logan, Utah 2019 ii Copyright © Sara Ann Kelly 2019 All Rights Reserved iii ABSTRACT River Hydrology, Morphology, and Dynamics in an Intensively Managed, Transient Landscape by Sara Ann Kelly, Doctor of Philosophy Utah State University, 2019 Major Professor: Dr. Patrick Belmont Department: Watershed Sciences Rivers sculpt Earth’s surface, and carry with them eroded and dissolved materials from the landscape. Deconvolving the fraction of material carried by rivers that is natural versus those that are caused by humans remains a challenging task for river science and management. Many rivers in the US and globally are impaired for excessive amounts of sediment, which limits the ecological integrity, recreation potential, and municipal, agricultural, and industrial water use. To inform water quality policy and management strategies, advances are needed to better understand factors influencing delivery of water and sediment to rivers, and the response of rivers to changes in those factors . Here, I study the Minnesota River Basin (MRB), where geologic history, land use, and recent streamflow increases have created rapidly adjusting and exceedingly muddy rivers. I answer three overarching questions: 1) have agricultural drainage practices contributed to streamflow increases in the upper Midwest?, 2) which flood events accomplish the most erosion in incising tributaries of the MRB?, and 3) where does most of the sediment come iv from and get transported to in the lower Minnesota River? Chapter 2 demonstrates that drainage practices are partly responsible for increasing streamflows in three intensively agricultural basins. Chapter 3 demonstrates that increased runoff in tributary basins has accelerated erosion of near-channel sources, such as bluffs. Further, I demonstrate that the 1.2 year return period floods cause the most erosion. Chapter 4 examines the downstream impacts of excessive sediment loading on the morphodynamics of the mainstem Minnesota River. I demonstrate that portions of the mainstem Minnesota River receiving excessive loading of coarse sediment from tributaries build broad alternate bars that create cross stream hydraulics favorable for meander migration and channel widening. Portions of the Minnesota River lacking significant bedload exhibit narrow bars that are less effective at driving meander migration and channel widening. The combined results suggest that agricultural drainage is increasing runoff, creating more erosive rivers, and recruiting material more readily from near-channel sources. These results support the notion that retention of agricultural drainage water would be an effective sediment reduction strategy. (242 pages) v PUBLIC ABSTRACT River Hydrology, Morphology, and Dynamics in an Intensively Managed, Transient Landscape Sara Ann Kelly Rivers create beautiful patterns and provide drinking water to millions. However an alarming number of rivers in the US and globally are threatened by excess sediment and nutrients. Agricultural rivers draining erodible soils are particularly vulnerable. Rivers of southern Minnesota provide a unique opportunity to study water and sediment dynamics in a naturally vulnerable system. Sediment reduction strategies are needed to ensure biological integrity and adequate water quality. Here, I address the questions: 1) have climate, land use practices, or both affected streamflows in Midwest agricultural rivers?, 2) which streamflows set the rate of river bluff erosion?, and 3) how do sediment supply and transport influence the form and behavior of the lower Minnesota River? Chapter 2 demonstrates, in three agricultural basins, that artificial drainage practices have decreased soil moisture, contributing to increases in streamflow. Chapter 3 quantifies river bluff erosion and identifies erosion by streamflows as the dominant erosion process. Erosion by common floods accomplishes the most cumulative bluff erosion. Bluff erosion contributes sediment to the Minnesota River. Chapter 4 shows how this coarse sediment influences the form and behavior of the Minnesota River. Therefore if flows were reduced, bluff erosion would slow, and the supply sediment to the Minnesota would slow, leading to less streambank erosion. Since streamflows have been increased by agricultural drainage practices, water retention solutions are needed to reduce high flows. vi ACKNOWLEDGMENTS First I would like to thank my major advisor, Dr. Patrick Belmont for believing that a 22 year old would one day finish her PhD. Patrick was always my biggest fan and mentor during this journey; I still tell myself, “you got this Kelly!” Thanks to Patrick, I had several amazing opportunities during my PhD including traveling to Ireland to attend a scientific meeting and prepare for teaching. Patrick rarely said no to extracurricular workshops and conference presentations, where he encouraged and supported me to give oral talks to further my presentation skills. Thank you for the opportunity to practice. I would also like to thank my committee members and collaborators Efi Foufoula- Georgiou, Peter Wilcock, Joe Wheaton, Jiming Jin, Karen Gran, and Phil Larson. Efi and Karen, thank you for being strong female role models for me to look up to. Peter, thank you for always making yourself available to meet with me. Many, many thanks for the use of your secret office during my final weeks of writing. I would also like to thank the many undergraduate and graduate students who helped with fieldwork over the years, including: Shayler Levine, Jay Hemmis, Michael Souffront, Keeling Schaffrath, Adam Fisher, Bruce Call, Angus Vaughan, Devon Libby, and Zachary Hilgendorf. I would also like to thank post-doctoral fellows Karthik Kumarasamy and Brendan Murphy for appreciated insight and assistance over the years. Zeinab Takbiri co-authored chapter 2 with me and was a pleasure to work with. Finally I would like to thank my family. Mom and Jen, I know it wasn’t easy living with me while I worked on my PhD. Thanks for always being supportive. Mike and Dad, while I don’t see you often I know you’re always there for me. Corey, thank you for your support and friendship. vii The material in chapter 2 is based upon work supported by the National Science Foundation (Grant No. EAR-1209402) under the Water Sustainability and Climate Program (WSC): REACH (REsilience under Accelerated CHange), and by the National Science Foundation Graduate Research Fellowship Program under Grant No. 1147384. This research was supported by the Utah Agricultural Experiment Station, Utah State University, and approved as journal paper number 8938. The authors would like to thank Jon Czuba at Indiana University, and Karthik Kumarasamy, Eden Furtak-Cole, and Mitchell Donovan at Utah State University for their input. Thank you to Alexander Bryan at the Northeast Climate Science Center for generously providing evapotranspiration data from Bryan et al. 2015. Funding for AmeriFlux data resources was provided by the U.S. Department of Energy’s Office of Science. The material in chapter 3 is based upon work supported by the Geological Society of America Graduate Student Research Grant, the National Science Foundation (NSF) Graduate Research Fellowship Program (grant no. 1147384), the NSF Water Sustainability and Climate (WSC) – Category 2 grant (EAR- 1209445 ). Authors thank Peter Wilcock, Jack Schmidt, Joe Wheaton, and Jiming Jin, as well as current and former members of the Belmont Hydrology and Fine Sediment Laboratory for discussions. Two anonymous reviewers provided useful feedback. We thank Brendan Murphy for writing a Matlab script for point cloud rotation (Appendix B). Additional gratitude is extended to Se Jong Cho, St. Anthony Falls Research Laboratory; Stephanie Day, North Dakota State University; Karen Gran, University of Minnesota, Duluth; Philip Larson, Ben Von Korff, and many Geography Department undergraduate and graduate students, Minnesota State University, Mankato; Andy Wickert University of Minnesota, Minneapolis;